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Lexicon MPX200 Dual-channel Effects Processor By Paul White
Published August 2001


Paul White tests Lexicon's new multi‑effects unit, which offers the classy sound quality of the MPX500 at an even more affordable price point.

Lexicon's new MPX200 effects processor is priced between their existing MPX100 and MPX500 machines and is designed to offer the more expensive unit's sound quality, but with reduced editability. The unit combines dual effects processors with a digital compressor, and the front‑panel layout breaks the mould of the earlier MPX units in having few physical controls and rather a lot of status LEDs.

Powered via an IEC mains inlet, the MPX200 features unbalanced jacks for the stereo analogue I/O, with 24‑bit A‑D/D‑A conversion, and phono connectors for coaxial S/PDIF digital I/O running at 44.1kHz. An Input knob on the front panel sets input level, with visual feedback via dual three‑segment bar‑graph meters. MIDI In and Out/Thru sockets are also fitted for remote parameter control, patch dumping and so forth, and the choice of MIDI Out or Thru is software selectable.

The inputs have a fairly high impedance and can therefore be used directly with electric guitars — plugging an input into only the right channel feeds both channels for mono operation. The manufacturer's specifications quote a dynamic range of 95dB using the analogue connections, or 100dB when working entirely digitally. A novel touch is that the left output jack socket is of a TRS type, and can drive stereo headphones directly if required. A further TRS jack allows a footswitch to be connected for remotely engaging the unit's bypass mode.

The MPX200's 24‑bit algorithms embrace all the usual reverb and ambience treatments, as well as tremolo, rotary‑speaker emulation, chorus, flange, pitch, detune and delay (up to 5.5 seconds). There's also a handful of special effects, including infinite reverb and a few weird pitch‑shifting tricks. There are several routing options for the two internal processors, which allow them to be used in series, in parallel, as independent mono blocks, or in a dual mono‑in/stereo‑out setup. In the latter case, the two stereo effect outputs are mixed. Front panel icons depict the four possible routing options, and each has a status LED so that you know which one is selected.

The Edit button brings up any one of eight different effects parameters in a three‑digit LED display, whereupon it can be edited using the unit's main rotary encoder — the currently selected parameter is shown by eight Edit status LEDs to the left of this LED display. Similarly, the Load button shows which of the 304 programs (240 preset and 64 user) is active. The rotary encoder can then select another, if required, the new program being confirmed with another press of the Load button — the patch change takes between one and two seconds.

All the possible routing configurations are provided in the factory presets, so you never have to get involved in setting any of them up from scratch. Instead, you just pick a suitable one, tweak the parameters to your requirements and then save the result in one of the user memories using the Store button. Not having an alpha numeric readout means you need to keep the manual handy when selecting effects programs, otherwise you don't really know which patch is which, though the LED matrix on the front panel does show what types of effects are being used once a patch has been loaded.

The built‑in compressor has its own Bypass button and a four‑segment LED gain‑reduction meter, while the main Bypass button can be configured either to mute the MPX200's output or simply to bypass all the effects processing. Holding down this latter button for two seconds accesses global system parameters. A Tap button allows you to quickly match relevant effects settings to tempo, and doubles as a Cancel button — the internal LED flashes whenever the current patch allows any parameter to be sync'ed in this way. (A chart in the manual shows which presets offer tempo‑sync'ing facilities.) The Tap and Store keys can also be used to access a MIDI learn mode, designed to simplify the process of assigning external MIDI messages to control internal parameters.

<h3>The Effects</h3>

The compressor always comes before the main effects block and only affects the signals feeding into the effects, not any dry component mixed in with them. Of course, being a digital processor, it can't prevent input overloads as it comes after the A‑D conversion stage. It requires a little bit of a workaround if you want to get the compression on its own (feeding the compressor into a single delay effect with a delay time of zero), though there are presets provided for doing this. If the dual mono‑in/stereo‑out effects configuration is used, then this workaround allows you to mix a compressed dry sound together with reverb generated from it.

The compressor's Ratio parameter can be adjusted from 2:1 up to 10:1 in four steps and the Attack and Release parameters are calibrated in milliseconds. Given that the MPX200 is designed to be a simple unit to operate, I'm rather surprised that there's no automatic option for setting the time constants, as I feel that far more people have difficulty setting up compressors than effects. However, the compressor sounds very smooth and musical and is particularly flattering to guitar. For patches where the original signal is not compressed, the compressor enables the effect level to be made more even.

The most important of the editable parameters for the dual multi‑effects is Adjust. This functions differently depending on the patch selected, with several effects parameters often linked so that they are changed simultaneously — the overall result is generally more appropriate than you'd get if you were only adjusting one parameter. In addition there is the EQ parameter, providing tonal adjustment, and level‑setting parameters.

On Test

The MPX200 sports a large LED matrix, which offers audio and gain‑reduction metering, as well as various status indicators.The MPX200 sports a large LED matrix, which offers audio and gain‑reduction metering, as well as various status indicators.

After running a few tests, I could detect very little difference between the sound quality of the MPX200 and that of the more flexible MPX500. Naturally, the reverbs are the stars of the show, creating a convincing sense of space and depth without submerging the dry sound or making it seem detached from the reverb that follows it. The small room and ambience programs are particularly impressive, especially compared with some software plug‑ins which often have to economise on CPU power.

The delay and modulation effects also stand up very well. OK, so the rotary speaker sounds more like a flange/chorus hybrid, and the pitch‑shifting still reveals the expected side effects, but both are very usable — the pitch‑shifting is fabulous for mixing with the dry sound for gentle detuning effects, for example. If you've heard an MPX‑series processor before, you'll have a good idea what to expect from these effects, and though you can only have two effects plus a compressor running at once, the result is still richer and classier than produced by most cheap multi‑effects boxes.

The operating system is very intuitive, not least because of the limited editability, and the unit would therefore be suitable even for users who have had little previous experience with effects. I find not being able to name patches somewhat irritating, but at some point the designers have to decide what they can offer for a given price and what they can't. In this case, they've decided to keep the intensely nice‑sounding algorithms, and I'm not about to argue with that logic.

Simple Pleasures


Lexicon have not done anything radically new in the MPX200, beyond adding a digital compressor to the input, but they have succeeded in producing an affordable unit that still delivers an expensive sound, albeit with limited editing. Anyone wanting the same sound with more control can save up for the more powerful MPX500, but if you like an easy life, yet find completely fixed presets too restricting, then the MPX200 could be for you.

Tapping In Time

The Tap button offers a number of options for sync'ing relevant time parameters to your music, the simplest of which is to set the tempo by hitting the button in time with the track. Holding the Tap button down, on the other hand, causes the tempo to automatically set itself according to the timing of transient sounds fed into the input, a feature which could be useful where you're trying to match the delay to an existing rhythm groove. The tempo can also be sync'ed to incoming MIDI timing information, if required.

Note that not all delay‑based effects can make use of the Tap button's tempo‑setting abilities. However, in such cases where tempo‑sync'ing is not available, the delay time will usually be tweakable by changing the effect's Adjust parameter. Where the Tap functions are available, the tempo setting is stored as part of the patch. However, there's a system option which allows you to override this setting with the most recent tempo value you've set.


  • Easy to use.
  • High‑quality Lexicon reverbs, including Ambience patches.
  • Digital compressor built in.


  • Displays only patch numbers, not names.
  • Editing may be too limited for some users.


Good‑sounding multi‑effects, with a compressor and quality reverb algorithms, at an attractive price.